<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>背景</title>
  <style>
    .box {
      width: 500px;
      height: 500px;
      background: linear-gradient(45deg, transparent 75%, #bbb 0),
      linear-gradient(225deg, transparent 75%, #bbb 0),
      linear-gradient(45deg, transparent 75%, #bbb 0),
      linear-gradient(225deg, transparent 75%, #bbb 0);
      background-position: 0 0, 15px 15px, 15px 15px, 30px 30px;
      background-size: 30px 30px;
    }
    .box2{
      width: 700px;
      height: 200px;
      background: hsl(20, 40%, 90%);
      background-image: linear-gradient(90deg, #fb3 11px, transparent 0),
      linear-gradient(90deg, #ab4 23px, transparent 0),
      linear-gradient(90deg, #655 41px, transparent 0);
      background-size: 41px 100%, 61px 100%, 83px 100%;
    }
  </style>
</head>
<body>
<div class="box"></div>
<div class="box2"></div>
</body>
</html>